<!DOCTYPE html>
<html>
    <head>
        <title>Bootstarp demo</title>
        <meta name="viewport" content="width=device-width initial-scale=1.0">
        <link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
    </head>
    <body>
        <div class="container" style="border: 1px solid red;">
            <h1>Hello, world!</h1>
        </div>
        <div class="container" style="boder: 1px solid red;">
            <div class="row">
                <div class="col-9" style="border: 1px solid blue;">
                    <div style="height: 500px;">内容区</div>
                </div>
                <div class="col-3" style="border: 1px solid blue;">
                    <div style="height: 500px;">侧边栏</div>
                </div>
            </div>
        </div>
        <footer class="container" style="border: 1px solid red;">
            底部 footer 区域
        </footer>
    </body>
</html>